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Evolution of a 72-Kilobase Cointegrant, Conjugative Multiresistance Plasmid in Community-Associated Methicillin-Resistant Staphylococcus aureus Isolates from the Early 1990s. Antimicrob Agents Chemother 2019; 63:AAC.01560-19. [PMID: 31501140 DOI: 10.1128/aac.01560-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 09/03/2019] [Indexed: 12/13/2022] Open
Abstract
Horizontal transfer of plasmids encoding antimicrobial resistance and virulence determinants has been instrumental in Staphylococcus aureus evolution, including the emergence of community-associated methicillin-resistant S. aureus (CA-MRSA). In the early 1990s, the first CA-MRSA strain isolated in Western Australia (WA), WA-5, encoded cadmium, tetracycline, and penicillin resistance genes on plasmid pWBG753 (∼30 kb). WA-5 and pWBG753 appeared only briefly in WA; however, fusidic acid resistance plasmids related to pWBG753 were also present in the first European CA-MRSA isolates at the time. Here, we characterize a 72-kb conjugative plasmid, pWBG731, present in multiresistant WA-5-like clones from the same period. pWBG731 was a cointegrant formed from pWBG753 and a pWBG749 family conjugative plasmid. pWBG731 carried mupirocin, trimethoprim, cadmium, and penicillin resistance genes. The stepwise evolution of pWBG731 likely occurred through the combined actions of IS257, IS257-dependent miniature inverted-repeat transposable elements (MITEs), and the BinL resolution system of the β-lactamase transposon Tn552 An evolutionarily intermediate ∼42-kb nonconjugative plasmid, pWBG715, possessed the same resistance genes as pWBG731 but retained an integrated copy of the small tetracycline resistance plasmid pT181. IS257 likely facilitated the replacement of pT181 with conjugation genes on pWBG731, thus enabling autonomous transfer. Like conjugative plasmid pWBG749, pWBG731 also mobilized nonconjugative plasmids carrying oriT mimics. It seems likely that pWBG731 represents the product of multiple recombination events between the WA-5 pWBG753 plasmid and other mobile genetic elements present in indigenous community-associated methicillin-sensitive S. aureus (CA-MSSA) isolates. The molecular evolution of pWBG731 saliently illustrates how diverse mobile genetic elements can together facilitate rapid accrual and horizontal dissemination of multiresistance in S. aureus CA-MRSA.
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Abstract
Strains of Staphylococcus aureus, and to a lesser extent other staphylococcal species, are a significant cause of morbidity and mortality. An important factor in the notoriety of these organisms stems from their frequent resistance to many antimicrobial agents used for chemotherapy. This review catalogues the variety of mobile genetic elements that have been identified in staphylococci, with a primary focus on those associated with the recruitment and spread of antimicrobial resistance genes. These include plasmids, transposable elements such as insertion sequences and transposons, and integrative elements including ICE and SCC elements. In concert, these diverse entities facilitate the intra- and inter-cellular gene mobility that enables horizontal genetic exchange, and have also been found to play additional roles in modulating gene expression and genome rearrangement.
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Fišarová L, Pantůček R, Botka T, Doškař J. Variability of resistance plasmids in coagulase-negative staphylococci and their importance as a reservoir of antimicrobial resistance. Res Microbiol 2018; 170:105-111. [PMID: 30503569 DOI: 10.1016/j.resmic.2018.11.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 11/09/2018] [Accepted: 11/22/2018] [Indexed: 11/25/2022]
Abstract
Coagulase-negative staphylococci (CoNS) are an important cause of human and animal diseases. Treatment of these diseases is complicated by their common antimicrobial resistance, caused by overuse of antibiotics in hospital and veterinary environment. Therefore, they are assumed to serve as a reservoir of resistance genes often located on plasmids. In this study, we analyzed plasmid content in 62 strains belonging to 10 CoNS species of human and veterinary origin. In 48 (77%) strains analyzed, 107 different plasmids were detected, and only some of them showed similarities with plasmids found previously. In total, seven different antimicrobial-resistance genes carried by plasmids were identified. Five of the CoNS staphylococci carried plasmids identical with either those of other CoNS species tested, or a well characterized Staphylococcus aureus strain COL, suggesting plasmid dissemination through horizontal transfer. To demonstrate the possibility of horizontal transfer, we performed electroporation of four resistance plasmids among Staphylococcus epidermidis, Staphylococcus petrasii, and coagulase-positive S. aureus strains. Plasmids were transferred unchanged, were stably maintained in recipient strains, and expressed resistance genes. Our work demonstrates a great variability of plasmids in human and veterinary staphylococcal strains and their ability to maintain and express resistance plasmids from other staphylococcal species.
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Affiliation(s)
- Lenka Fišarová
- Masaryk University, Department of Experimental Biology, Kotlářská 2, 611 37 Brno, Czech Republic.
| | - Roman Pantůček
- Masaryk University, Department of Experimental Biology, Kotlářská 2, 611 37 Brno, Czech Republic.
| | - Tibor Botka
- Masaryk University, Department of Experimental Biology, Kotlářská 2, 611 37 Brno, Czech Republic.
| | - Jiří Doškař
- Masaryk University, Department of Experimental Biology, Kotlářská 2, 611 37 Brno, Czech Republic.
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Wassenaar TM, Ussery DW, Ingmer H. The qacC Gene Has Recently Spread between Rolling Circle Plasmids of Staphylococcus, Indicative of a Novel Gene Transfer Mechanism. Front Microbiol 2016; 7:1528. [PMID: 27729906 PMCID: PMC5037232 DOI: 10.3389/fmicb.2016.01528] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 09/12/2016] [Indexed: 11/13/2022] Open
Abstract
Resistance of Staphylococcus species to quaternary ammonium compounds, frequently used as disinfectants and biocides, can be attributed to qac genes. Most qac gene products belong to the Small Multidrug Resistant (SMR) protein family, and are often encoded by rolling-circle (RC) replicating plasmids. Four classes of SMR-type qac gene families have been described in Staphylococcus species: qacC, qacG, qacJ, and qacH. Within their class, these genes are highly conserved, but qacC genes are extremely conserved, although they are found in variable plasmid backgrounds. The lower degree of sequence identity of these plasmids compared to the strict nucleotide conservation of their qacC means that this gene has recently spread. In the absence of insertion sequences or other genetic elements explaining the mobility, we sought for an explanation of mobilization by sequence comparison. Publically available sequences of qac genes, their flanking genes and the replication gene that is invariably present in RC-plasmids were compared to reconstruct the evolutionary history of these plasmids and to explain the recent spread of qacC. Here we propose a new model that explains how qacC is mobilized and transferred to acceptor RC-plasmids without assistance of other genes, by means of its location in between the Double Strand replication Origin (DSO) and the Single-Strand replication Origin (SSO). The proposed mobilization model of this DSO-qacC-SSO element represents a novel mechanism of gene mobilization in RC-plasmids, which has also been employed by other genes, such as lnuA (conferring lincomycin resistance). The proposed gene mobility has aided to the wide spread of clinically relevant resistance genes in Staphylococcus populations.
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Affiliation(s)
| | - David W Ussery
- Department of Biomedical Informatics, University of Arkansas for Medical Sciences Little Rock, AR, USA
| | - Hanne Ingmer
- Department of Veterinary Disease Biology, Faculty of Health and Medical Sciences, University of Copenhagen Copenhagen, Denmark
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Barigye R, Schaan L, Gibbs PS, Schamber E, Dyer NW. Diagnostic Evidence of Staphylococcus Warneri as a Possible Cause of Bovine Abortion. J Vet Diagn Invest 2016; 19:694-6. [DOI: 10.1177/104063870701900613] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Following a routine necropsy of a bovine fetus aborted at 5 months of gestation, placenta, fetal tissue samples, and stomach contents were subjected to a number of laboratory tests. Staphylococcus warneri was isolated in pure culture from the lung, liver, and stomach contents, whereas the placenta yielded S. warneri and a number of contaminants. Gross evaluation of agar plates showed predominant colonies to be morphologically consistent with those of S. warneri and the identity of the agent was further confirmed on a Trek Diagnostic Systems Sensititre, gram-positive identification (GPID) plate. Microscopic evaluation of fetal tissue sections showed extensive necrotizing lesions of the tongue, lung, and placenta in which there were numerous coccoid shaped gram-positive bacteria with morphology consistent with Staphylococcus spp. These results provide strong diagnostic evidence of S. warneri as a possible cause of bovine abortion and suggest there should be further investigations into the abortivirulence of this agent.
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Affiliation(s)
- Robert Barigye
- Department of Veterinary Diagnostic Services, North Dakota State University
- Department of Veterinary and Microbiological Sciences, North Dakota State University
| | - Lynn Schaan
- Department of Veterinary Diagnostic Services, North Dakota State University
| | - Penelope S. Gibbs
- Department of Veterinary Diagnostic Services, North Dakota State University
- Department of Veterinary and Microbiological Sciences, North Dakota State University
| | - Ev Schamber
- Department of Veterinary Diagnostic Services, North Dakota State University
| | - Neil W. Dyer
- Department of Veterinary Diagnostic Services, North Dakota State University
- Department of Veterinary and Microbiological Sciences, North Dakota State University
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Lee JH, Jeong DW. Characterization of Mobile Staphylococcus equorum Plasmids Isolated from Fermented Seafood That Confer Lincomycin Resistance. PLoS One 2015; 10:e0140190. [PMID: 26448648 PMCID: PMC4598088 DOI: 10.1371/journal.pone.0140190] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Accepted: 09/22/2015] [Indexed: 12/18/2022] Open
Abstract
The complete nucleotide sequences of lincomycin-resistance gene (lnuA)-containing plasmids in Staphylococcus equorum strains isolated from the high-salt-fermented seafood jeotgal were determined. These plasmids, designated pSELNU1–3, are 2638-bp long, have two polymorphic sites, and encode typical elements found in plasmids that replicate via a rolling-circle mechanism including the replication protein gene (rep), a double-stranded origin of replication, a single-stranded origin of replication, and counter-transcribed RNA sequence, as well as lnuA. Plasmid sequences exhibit over 83% identity to other Staphylococcus plasmids that harbor rep and lnuA genes. Further, three pairs of identified direct repeats may be involved in inter-plasmid recombination. One plasmid, pSELNU1, was successfully transferred to other Staphylococcus species, Enterococcus faecalis, and Tetragenococcus halophilus in vitro. Antibiotic susceptibility of the transconjugants was host-dependent, and transconjugants maintained a lincomycin resistance phenotype in the absence of selective pressure over 60 generations.
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Affiliation(s)
- Jong-Hoon Lee
- Department of Food Science and Biotechnology, Kyonggi University, Suwon, 443–760, Republic of Korea
| | - Do-Won Jeong
- Department of Food Science and Biotechnology, Shinansan University, Ansan, 425–792, Republic of Korea
- * E-mail:
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Piessens V, De Vliegher S, Verbist B, Braem G, Van Nuffel A, De Vuyst L, Heyndrickx M, Van Coillie E. Characterization of coagulase-negative staphylococcus species from cows’ milk and environment based on bap, icaA, and mecA genes and phenotypic susceptibility to antimicrobials and teat dips. J Dairy Sci 2012; 95:7027-38. [DOI: 10.3168/jds.2012-5400] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 08/04/2012] [Indexed: 11/19/2022]
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Bjorland J, Bratlie MS, Steinum T. The smr gene resides on a novel plasmid pSP187 identified in a Staphylococcus pasteuri isolate recovered from unpasteurized milk. Plasmid 2007; 57:145-55. [PMID: 17074390 DOI: 10.1016/j.plasmid.2006.08.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Revised: 04/25/2006] [Accepted: 08/06/2006] [Indexed: 11/26/2022]
Abstract
UNLABELLED This work describes a novel plasmid pSP187 (5550 bp) carrying the small multidrug resistance determinant smr encoding resistance to quaternary ammonium compounds (QACs). pSP187 was identified in a Staphylococcus pasteuri isolate recovered from bulk milk in a dairy cattle herd in Norway. Sequence analysis revealed 6 putative ORFs in addition to the smr gene within a cassette with identical genetic organization to that found in the pSK41-like Staphylococcus aureus plasmid pTZ22. A protein homology search suggested the gene product of ORF7 to be a putative replication initiation protein, while ORF2 was predicted to encode a protein homologous to members of FtsK/SpoIIIE cell division-DNA segregation protein families. Sequence similarities to some initiator proteins of rolling circle replicons (RCR) indicated that pSP187 uses a RCR mode of replication, supported by the detection of intermediate ssDNA using S1 nuclease treatment and hybridization analysis. Interestingly, a 30-bp sequence found upstream from ORF7 showed high similarity to other dyad symmetry motifs proposed as putative double-strand origins of replication in the plasmids pGI3 (Bacillus thuringiensis), pSTK1 (Bacillus stearothermophilus), and pER1-2 (Streptococcus thermophilus). IN CONCLUSION The novel smr-containing plasmid pSP187 is the first member of RCR group VI to be identified in a Staphylococcus sp.
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Affiliation(s)
- Jostein Bjorland
- Department of Production Animal Clinical Sciences, Norwegian School of Veterinary Science, P.O. Box 8146 Dep, N-0033 Oslo, Norway.
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